The French parliament has approved a groundbreaking law that makes psychological violence an offence as part of a broader range of measures aimed at improving protection of victims of domestic abuse.

Magistrates have criticised the bill, fearing that it will be hard to define what exactly constitutes such mental abuse. They say it will be difficult to prove in court. The law was proposed by members of parliament from both the ruling majority and the leftist opposition and won the backing of the centre-right government.

"We have introduced an important measure here, which recognises psychological violence, because it isn't just blows [that hurt] but also words," Nadine Morano, the minister for family affairs, told the lower house of parliament.

Anyone found guilty of breaking the law faces up to three years in jail and a €75,000 ($91,530) fine. The bill defines mental violence as "repeated acts which could be constituted by words or other machinations, to degrade one's quality of life and cause a change to one's mental or physical state".

Morano said witnesses could be called on to testify in such cases, and doctors' certificates detailing a patient's descent into nervous depression could be used as evidence.

"The judge could [also] take into consideration letters, SMSs or repetitive messages, because one knows that psychological violence is made up of insults," she added.

The law can be used to protect both women and men who might suffer from such abuse. Parliamentarians have acknowledged, however, that women are the main victims.

According to government statistics, 675,000 women have suffered physically violent attacks over the past two years, with 166 women murdered in 2007 and 156 in 2008.

Killings arising from domestic violence account for 20% of all murders across the country.

Morano said the main abuse helpline for women in France received 90,000 calls a year.